Secret latch

ABSTRACT

A second latch for use on a door has the customary bolt retractable by turning an inner knob which is always free to rotate, and also by turning an outer knob when such outer knob is freed for rotation by the momentary axial depression by thumb pressure of a pin tumbler lock cyclinder located in the outer knob. When greater security is desired a push button in the inner knob can be moved to a hold position to prevent axial depression of the lock cylinder thereby preventing the release of the outer knob for rotation. The lock cylinder may be rotated at all times by a proper key in the customary manner for retracting the bolt.

[ NOV.4,1975

[ SECRET LATCH [75] Inventor: Ernest L. Schlage, Burlingame,

Calif.

[73] Assignee: Schlage Lock Company, San

Francisco, Calif.

[22] Filed: July 1, 1974 [21] Appl. No.: 484,773

UNITED STATES PATENTS Fipps 70/195 Fredholm 292/5 Maruri 70/145 PrimaryExaminerAlbert G. Craig, Jr. Attorney, Agent, or Firm-Lothrop & West[57] ABSTRACT A second latch for use on a door has the customary boltretractable by turning an inner knob which is always free to rotate, andalso by turning an outer knob when such outer knob is freed for rotationby the momentary axial depression by thumb pressure of a pin tumblerlock cyclinder located in the outer knob. When greater security isdesired a push button in the inner knob can be moved to a hold positionto prevent axial depression of the lock cylinder thereby preventing therelease of the outer knob for rotation. The lock cylinder may be rotatedat all times by a proper key in the customary manner for retracting thebolt.

18 Claims, 18 Drawing Figures US. Patent Nov. 4, 1975 Sheet 1 of63,916,656

U.S. Patent Nov. 4, 1975 Sheet 2 of6 3,916,656

US. atent Nov. 4, 1975 Sheet4 0f6 3,916,65

US. Patent Nov. 4, 1975 Sheet 5 of6 3,916,656

US. Patent Nov. 4, 1975 Sheet 6 of 6 SECRET LATCH In buildings and thelike there are various instances in which security requirements varyfrom time to time. Sometimes an ordinary amount of security is requiredbut at other times less security and easier access is helpful. Also,there are instances in which ordinary security should be maintained withrespect to one type of user, whereas lesser security is more convenientand satisfactory for other types of users. For example, a large, privateworkroom having a door onto a public hall is provided with the normalamount of security in off business hours in that an access door betweenthe room and the hall is secured with the customary, key operated knoblock. During business hours, for example, the same degree of securitymust be maintained as to members of the general public utilizing thehall. But clerks or others having normal access to the room can beafforded easier access going into the room from the hall, so that theirwork is not impeded. While each clerk can be given his own key, this iscumbersome and bothersome. There is a requirement for easier access fromthe hall into the room by privileged users, such as clerks and the like,but not for the general public.

It is therefore an object of the invention to provide a secret latchwhich can be utilized to afford normal keyed security to the door onwhich it is installed, but which can be more readily operated without akey by those having appropriate information.

Another object of the invention is to provide a secret latch that canreadily be incorporated, with very few structural changes, in a lock setof customary construction.

Another object of the invention is to provide a secret latch that can beeasily shifted from its maximum security condition to an intermediatesecurity condition.

Another object of the invention is to provide a lock mechanism that hasspecial characteristics but does not differ in appearance, wheninstalled, from a standard lock mechanism.

A further object of the invention is to provide a secret latch ofgenerally improved construction and having attributes not normallyavailable in customary latch sets.

A further object of the invention is in general to provide an improvedlatch or lock mechanism.

Other objects, together with the foregoing, are attained in theembodiments of the invention described in the accompanying descriptionand illustrated in the accompanying drawings, in which:

FIG. 1 is a cross-section on a generally horizontal plane through theaxis of one form of secret latch con-,

structed pursuant to the invention and shown mounted on a door panelcooperating with a door frame, some parts being omitted for clarity;

FIG. 2 is a cross-section, the plane of which is indicated by the line22 of FIG. 1; v

FIG. 3 is a cross-section, the plane of which is indicated by the line33 of FIG. 2;

FIG. 4 is a side elevation of a fragment of the secret latch mechanismof FIG. 1;

FIG. 5 is an isometric perspective of a generalized form of secretlatch, most of the parts being disclosed in diagrammatic form;

FIG. 6 is a view comparable to FIG. 1, with a portion broken away,showing a modified form of interior construction;

FIG.7 is a detail in elevation, the plane of view being indicated by theline 7-7 of FIG. 6;

FIG. 8 is a view comparable to FIG. 1, but showing a further modifiedform of device, portions being broken away to disclose a modifiedinterior construction;

FIG. 9 is a cross-section, the plane of which is indicated by the line9-9 of FIG. 8;

FIG. 10 is a cross-section, the plane of which is indicated by the lineII)I0 of FIG. 8;

FIG. I1 is a view comparable to FIG. 1 but showing a still furthermodified form of the invention, portions being broken away to disclose amodified interior arrangement;

FIG. 12 is a cross-section, the plane of which is indicated by the lineI2I2 of FIG. II;

FIG. 13 is a cross-section, the plane of which is indicated by the lineI3I3 of FIG. II;

FIG. 14 is an interior elevation, the plane of which is indicated by theline 14-14 of FIG. 11;

FIG. 15 is a cross-section, the plane of which is indicated by the line15-15 of FIG. 11;

FIG. 16 is a view comparable to FIG. 1 but showing an even furthermodified form of the device, portions being broken away to disclose theparticular interior construction;

FIG. I7 is a detail in plan and cross-section, the general plane of thefigure being indicated by the line 1717 of FIG. 16;

FIG. 18 is a cross-section, the plane of which is indicated by the lineI8-I8 of FIG. 17.

In a typical environment; for example, between a public hallway orpassageway and an interior workroom, such as a file room or clerk room,there is provided a door frame 6 of the customary kind, including astrike box 7 and a strike plate 8. Cooperating with the door frame is adoor panel 9 adapted to swing about a hinge axis spaced from the plate8. The panel 9 includes an edge bore 11 in which the customary or anystandard, cylindrical bolt or latch mechanism 12 is disposed forreciprocation. Intersecting the bore 11 and extending through the doorpanel between the exterior and the interior is a cross bore 13. Thepanel arbitrarily divides the space so that the side 14 is referred toas the inside or interior, whereas the side I6 is referred to as theexterior or outside.

Mounted in the bore 13 and interconnected in the customary way with thelatch mechanism 11 is the housing 17 of a lock or latch unit. Arepresentative device of this general sort is shown in Pat. No.2,834,194, issued May 13, 1958, to E. L. Schlage et al. and assigned tothe assignee of this application, and is also found in numerousresidential and commercial installations throughout this country. Thehousing I7 has an appropriate hub I8 on the interior side surrounded bya decorative escutcheon I9 and serving as a bearing mount for rotationof an inner spindle 21 about a through axis 22. The spindle 21 carriesan inner knob 23 rotatable therewith about the axis. Operation of theknob 23 is effective through the spindle 21 to actuate a rollbackmechanism 24 to withdraw the latch bolt 112 to an inactive positionreleasing the otherwise retained door panel from the door frame in thecustomary fashion.

In a similar fashion, the housing 17 includes a frame plate 26 having ahub 27 within which an outer spindle 28, unless restrained, is rotatableabout the axis 22. A knob 29 on the outer spindle is disposednext to anescutcheon 30 and, if free to rotate, is efiective through 3 the spindleupon the roll-back mechanism 24, so that the latch member 12 can beretracted from the exterior side as well as from the interior side, bothknobs working independently but being effective for the same purpose.

There is a control governed from the interior for normally holding theexterior knob 29 immovable with respect to the frame or housing 17, sothat, in effect, the door is exteriorly locked. Conveniently nestedwithin the knob 23 is an interior button 31 that is in general movablealong the axis 22 and is normally spring urged into an outermost orright-hand position, as seen in FIG. 1. The arrangement for thisincludes a shell 32 disposed within the spindle 21 and containing aspring 33 pressing against the outermost part of the button 31. Carriedby the button (FIGS. 3 and 4) is an extending lug 34 movable within acut-out 36 in the wall of the spindle 21. The cut-out preferably has aninclined face 37 (FIG. 4) and a re-entrant notch 38. A user can depressthe button 31 toward the left in FIG. 1, compressing the spring 33 andmoving the lug 34 along the cutout to an extreme left-hand position,whereupon the user can turn the button 31 about the axis 22 and let gothe button so that the spring urges the lug 34 into the recess 38 tohold the button in its inner location axially abutting the shell 32. Thebutton can be released by a slight inward pressure to remove the lug 34from the notch 38 and then can be rotated counterclockwise so that thespring restores the button and the lug to its initial position.

The position of the button is effective to permit or to prevent axialtranslation of a locking bar 41 partly housed within the knob 23 andpartly housed within the housing 17 and extending along the axis 22. Thelocking bar 41 interengages with the end of the shell 32 againstrelative axial motion and for relative rotation therebetween. Thelocking bar has an offset 42 terminating in a pair of lugs 43 and 44.One of the lugs 43 is axially translatable in a slot 46 formed in oneend of the hub 27 included in'the housing 17, so that the locking bar 41is non-rotatable with respect to the stationary hub. The other lug 44 ismovable between a lock position (as shown in FIG. 1) in which the lug 44enters into and engages the sides of a slot 47 formed in the otherwiserotatable outer spindle 28. In this position of the parts, ascontinually urged by the wire spring 33, the locking bar interengageswith the stationary housing and the otherwise rotatable spindle topreclude rotation of the spindle. The exterior knob 29 is thus normallyheld against rotation, so that the outer knob is ineffective to withdrawthe latch bolt 12. If the locking bar 41 is in some fashion translatedtoward the right in FIG. 1 so that the lug 44 is removed from thespindle slot 47, the spindle is freely rotatable and the lock bolt orlatch can be withdrawn by the outer knob. Thus, whether the outer knobis locked or is free depends upon the axial position of the locking bar.

In accordance with the invention, unlocking movement of the locking barcan be accomplished from the exterior by appropriately operating a pintumbler lock mechanism 51 housed within the outer knob and spindle. Thespindle 28 has a slot 52 receiving the tongue or flag 53 of a pintumbler lock body 54 of the customary sort. Within the body 54 androtatable about the axis 22 is the customary lock plug 56 designed toreceive a proper key 57. Upon insertion of the key various tumbler pins58 are arranged within the lock mechanism, so that the plug 56 can berotated. Plug rotation is accompanied by rotation of a relatively flatdriver bar 59. The driver bar engages an actuating mechanism 61 alsoengaging a tube 62 effective upon rotation to withdraw the latch bolt 12in the customary way. Thus, when a proper key 57 is rotated, althoughthe outer knob 29 is held stationary, the latch bolt 12 is withdrawn bykey and entry can be had through the doorway, as is customary. As so fardescribed, the general operation of this lock or latch set issubstantially standard.

Pursuant to the present invention, however, an additional function isafforded. The notch 52 is the outer spindle 28 is made axially somewhatdeeper than usual, so that although the pin tumbler lock body 54 is wellconfined in the rotary sense, it is not confined in the axial sense.Inward pressure upon the outer end of the rotary plug 56 or upon thehousing 54, or both, is effective to translate the combined plug andhousing toward the right in FIG. 1. Although the driver bar 59 isaxially slidable within the fitting 61 and can impart rotation theretoin any axial position, the driver bar 59 is made somewhat longer thanusual in order to press upon a cup 63 concentric with the axis anditself bearing upon a spacer 64 engaged with a third lug 66 on thelocking bar 41. Thus, when pressure (with or without a key 57) isexerted toward the right on the body 54 and the plug 56, the driver bar59 is similarly translated and comparably translates the cup 63, thespacer 64 and the locking bar 41 to the right against the force of thespring 33. The amount of translation is sufficient to withdraw the lug44 from the slot in the outer spindle 28, thus releasing the knob 29 forrotation. Thereupon the user can rotate the knob and can withdraw thelatch bolt 12 from its locked position to its unlocked position withoutrotation of any key 57. When the knob is released, all parts are springreturned to the original locked position.

With this mechanism a user on the interior side 14 can depress thebutton 31 and can turn the button to hold it in location so that thelocking bar 41 is axially completely non-movable, the knob 29 is heldand the latch 12 cannot be withdrawn by the exterior knob. Furthermore,under these conditions the insertion of a proper key 57, althougheffective to rotate the locking mechanism 51 and in that fashion towithdraw the latch bolt 12, cannot translate the driver bar 59 nor thelocking bar 41 since the depressed and held button 31 acts as an axialstop and the outer knob 29 remains immobile. On the other hand, when thebutton 31 is released from the interior allowing lost motion between theshell 32 and the button itself, then anyone knowing of the extracapability of the lock body and plug, even without a key, can depressthe plug 56 and the locking mechanism thus releasing the outer knob 29for rotation, and by that means can withdraw the latch bolt 12 to gainaccess through the door to the interior. In this way there is providedan arrangement which, when the interior button 31 is depressed, afl'ordsnormal security to the lock set; that is, the outer knob 29 is immobilebut use of a proper key 57 will afford access to the interior. On theother hand, when the interior button 31 is released into its position asshown in FIG. 1, then a lesser degree of security is afforded in thatanyone, having knowledge, can depress the plug 56 by thumb pressure, canrotate the knob 29 to withdraw the latch bolt 12 and so can gain accessto the interior. The external appearance is standard and unchanged, soinspection of the lock set does not indicate its extra or secretcapability.

In a representative instance, the button 31 can be left in its innermosthold or locked position for the night, for example. The only access fromthe exterior to the interior is then by means of a proper key 57. Duringworking hours, however, if the button 31 is released, as shown, thenanyone having appropriate knowledge of the lock can by depressing theplug 56 gain access with out the usual key. Those with keys can alwaysgain access, and those without keys can gain access provided theinterior button 31 is released and they have the information that,unlike usual practice, the lock body and plug are not only rotatable,but are depressible or axially translatable. The casual public does nothave this information and since the lock set looks exactly the same fromthe exterior as other sets always requiring the use of a key for access,there is an opportunity to exclude the unknowing general public from thearea, but to make easy ingress for those having adequate information todepress the key actuated mechanism.

This general type of operation is shown for explanatory purposes indiagrammatic form in FIG. 5. The latch bolt 72 is connected to a slide73 movable with respect to the main frame 74. An interior knob 76carries a lug 77 forming part of the knob spindle 78 so that uponrotation of the knob 76, in at least one direction, the slide 73 ismoved toward the right in FIG. 5 and the latch bolt 72 is withdrawn. Ina similar fashion, there is provided an exterior knob 81 having aspindle 82 provided with a lug 83 bearing against the rear wall 84 ofthe slide 73, and effective when rotated, at least in one direction,also to withdraw the latch bolt 72. The latch bolt is restored by aspring 85 interposed between the wall 84 and the main frame 74. There isa key mechanism 87 of the pin tumbler type having a lock body 88disposed in the spindle 82 with the body flag 89 movable axially in alongitudinal slot 91 in the spindle. Within the body 89 is a relativelyrotatable lock plug 92 operable by a proper key 93. Rotation of the plugwithin the body is effective to rotate a locking bar 94 to rotate a lug96 bearing against the wall 84 and so withdraw the latch bolt.

Projecting from the inner knob 76 is a manually operable button 97pressed outwardly by a spring 98 and having a lug 99 movable into anotch 101, so that the button 97 can be retained in its hold ordepressed position. The spring 98 is effective normally to move a shell102 and a locking bar 103 to the left in FIG. 5. A lug 104 on thelocking bar is slidable in engagement with a notch 106 in the frame 74,while a lug 107 on the locking bar engages a notch 108 in the spindle82. The outer knob 81 is thus kept from rotating under all normalcircumstances. Even without the use of the key 93, pressure from theexterior toward the right along the axis of the mechanism is effectiveto translate the lock body 88, as well as the plug 92, within theremaining length of the slot 91, so that the driver bar 94 moves thelocking bar 103 to the right. This withdraws at least one of the lugs,such as 107, from the notch 108 and translates the shell 102 andcompresses the spring 98. The knob 81 is so released for exteriorrotation and the latch bolt 72 can be withdrawn thereby. However, whenthe button 97 is moved to its hold position and the lug 99 is moved intothe notch 101, axial pressure by the driver bar 94 is ineffective totranslate the locking bar 103 so that the outer knob remains fixed andheld against rotation and withdrawal of the latch 72.

The arrangement of FIG. 6 is substantially the same in general aspreviously described, but some of the details are different. In thisinstance the flat locking bar 111 has a shoulder 112 against which aspring 1 13 abuts through the intermediary of a washer 114. The springat the other end abuts a lug plate 116 mounted on a plug 1 18 againstwhich abuts a driver bar 119 controlled by a locking mechanism 121disposed in the outer knob 122 and of the same type as previouslydescribed. In the normal-location of the parts as shown in FIG. 6, forexample, the lug plate 116 and the plug 1 18 are positioned by thespring 113 so that a radially extending lug 123 on the, lug plateresides in both a slot 124 in the main housing 126 and also in a notch127 in the end of the spindle 128 of the outer knob. This locks theouter knob 122 against rotation. If, however, the locking mechanism 121is translated toward the right in the figure, the driver bar 119 movesthe plug 118 and the lug plate 116 to the right so that the lug 123disengages from the notch 127 and compresses the spring 113. Thismovement takes up most of the space available so the plug 118 resideseventually against a shoulder 129 near the end of the locking bar 111.In this position of the parts the knob 122 is released for customaryrotation and withdrawal of the latch bolt. A key 131 for the lockingmechanism 121 is effective as usual to operate the latch bolt under anycircumstances.

Upon occasion, it is desired to prevent the translation of the lockmechanism 121 to prevent freeing the outer knob 122 for rotation. Whenthat is the case, a button 132 within an inner knob 133 is depressed toits hold position. This is accomplished by a rotary connection 134between the button 132 and the locking bar 111 and by a lug 136 on thebutton operating in a cam notch 137 in a fixed sleeve 138. A flat 139 atthe end of the notch 137 holds the button 132 when it is pressed in andturned. Depression of the button translates the locking bar 111 to theleft so that the shoulder 129 thereon abuts against the end of the plug118 compressing the spring 113 and precluding translation of the lug 123out of the slot 124. By the turning and locking mechanism, the interiorbutton 132 can be kept in a hold position thus securing the outer knob122 against rotation and preventing depression of the locking mechanism121.

As a further variation, there is shown a mechanism in FIGS. 8, 9 and 10comparable to the mechanism shown in FIG. 1, but with a different lostmotion and spring arrangement. In this instance the parts not describedin detail are substantially the same as in connection with FIG. 1. Inthis instance the locking bar is made in two portions. There is aninterior locking bar 151 having lugs 43 and 44 exactly as in FIG. 1 andterminating in a portion 152 overlapping the forward portion 153 of anexterior locking bar 154 extending into the interior knob 156. Theoverlapping portions of the locking bars are aligned by through pins 157and 158 disposed in appropriate slots 159 and 161. There are washers 162and 163 that abut the pins 157 and 158 and also abut the ends of aninterposed spring 164 so that a resilient lost motion is afforded. Theexterior locking bar 154 carries a head 166 rotatably connected to abutton 167 axially translatable and rotatable with respect to theadjacent interior spindle 168 to which the knob 156 is attached. A lug169 on the button 167 operates within an irregular notch 171 formed inthe spindle 168.

Normally with the button 167 projected against the knob as a stop, asshown in FIG. 8, the spring 164 urges the interior locking bar 151 intoits exterior knob blocking position. The spring also forces the exteriorlocking bar 154 to the right, thus moving the button 167 to the right. Arim 172 on the button lodges against an inturned portion 173 of the knob156. When a locking mechanism 174 in the outer knob 176 is translated tothe right in FIG. 8, it also moves a driver bar 177 to the right, thusdisplacing the interior locking bar 151 into knob release position. Whenpressure on the locking mechanism 174 is released, the spring 164expands and forces the interior locking bar 151 to the left and backinto its notch position holding the exterior knob 176 against rotation.When this position is to be maintained, the interior button 167 istranslated to the left, in FIG. 8, and is rotated so that the lug 169moves into an axially confining, offset, flat portion of the notch 171and translates the exterior locking bar 154 to the left. This brings thepin 158 to the left end of its notch 161 and brings the right end of thenotch 159 against the pin 157. This, then, holds the interlocking bar151 against translation to the right, so that the knob 176 cannot bereleased.

In the modified form of device shown in FIGS. 11 to 15, inclusive, anarrangement generally similar to those preceding is furnished, but thereis a difference in the operation of the interior push button. The pushbutton, instead of being depressed in order to maintain the outer knobin its nonrotatable position, is, in effect, moved from a normal rotatedposition to a special hold rotated position.

In this arrangement a locking bar 181 is provided with a securing washer182 positioning an abutting washer 183 having a radial split therein andserving as a stop for one end of a suitable spring 184. The other end ofthe spring 184 bears against a slotted backing washer 186, in turnresting against the customarily provided, transverse slide 187. A spring188 in the interior spindle 189 projects the slide 187 to engage theinner' knob 191 with the spindle. When the slide 187 is moved inwardlyby an appropriate tool the knob 191 is released from the spindle, but inthe position shown the knob is held axially in position and for rotationwith the spindle.

The innermost end of the locking bar 181 is pivotally connected to abutton housing 192 having a lug 193 (FIGS. 14 and operating in a spindleslot having a circumferential portion 194 and having an axial mergingportion 196 open to the end rim 197 of the interior spindle.

For normal locking, the button 192 is disposed with the lug 193 at thetop (FIG. 14) end of the slot 194. Under these conditions translation ofthe locking bar 181 is prevented by interengagement of the lug 193 withthe inner wall of the circumferential slot 194. The button 192 has adiametral extension 201, so the button can be turned to position the lug193 at either end of the slot 194. In both instances the lug 193 servesas a stop against further translation of the locking bar 181 to theleft.

When the outer knob 198 is to be freed for rotation, a locking mechanism202, of the sort previously described, can be axially moved toward theright to displace the entire structure connected to the locking bar 181to the right but only provided the button 192 is positioned so that thelug 193 can freely traverse the axial portion 196 of the slot. Unlockingdepression of the mechanism 202 can be noted from the interior bywatching axial movement of the button 192. There is a detent cam 203utilizing force of the spring 184 to urge the button into either extremerotated position. By

proper rotation of the normally depressed button 192 the locking bar 181can be held in its unlocked condition or can be held in its locked orhold condition.

In a still further modification of the fundamental arrangement, as shownin FIG. 16, the mechanism is somewhat like that shown in FIGS. 8 to 10,inclusive. In this version, there is disclosed an arrangement in which,although interrelated, the locking and unlocking of the exterior knob isindependent of the inward movement of the cylinder lock mechanism.

In this arrangement, the exterior pin tumbler cylinder mechanism 206 canbe rotated, as usual, to withdraw the latch bolt by means of a key, butalso can be translated axially, as before, and when so translated causesthe driver bar 207 to release one of a pair of locking bars 208 and 209from their engagement with a relatively wide slot 211 (FIG. 17) in theexterior spindle 212. The two locking bars are similar in constructionand are fastened together in a limited sense for some guidance, but inmost other respects are independent. The locking bar 208, for example,carries a pin 213 extending into an elongated slot 214 in the otherlocking bar 209. Furthermore, the locking bar 208 has a C- shaped endportion 216 riding on the top and bottom of the locking bar 209. TheC-shaped end portion 216 abuts a notched washer 217 riding upon thelocking bar 209 and abutting one end of a coil spring 218. The other endof the spring 218 abuts a washer 219 resting against a turnable button221 mounted within the central opening of the inner knob 222. The button221 has the customary lug designed to operate in a slot 223 in theinterior spindle 224, as previously described.

In the operation of this structure when the lock mechanism 206 istranslated toward the right it engages and similarly translates thelocking bar 208 toward the right. This is against the urgency of thespring 218 because the portion 216 displaces the washer 217. At the sametime, because of the interconnection of the pin 213 and the slot 214,both of the locking bars 208 and 209 are translated far enough so thatneither interengages between the lock frame and the outer spindle, thusreleasing the exterior knob.

When it is desired to maintain the outer knob against rotation, then thebutton 221 is translated toward the left in FIG. 16 and is turned so asto be held in its leftmost position. That compresses the spring 218 andsimultaneously moves the locking bar 209 to the left enough to causeinterengagement of the left-hand end thereof in the wide slot 211 in theexterior spindle 212. In this way the locking bar 209 is held inrestraining position by the depressed button 221. Should one thenattempt to translate the locking mechanism 206 to the right, the attemptmust fail because the pin 213 is then in the right-hand end of the slot214 and cannot move the locking bar 209 because of the secure positionof the button 221. The only way then to withdraw the locking bar 209from its interengagement with the slot 211 is by rotating the interiorbutton 221 and permitting the spring 218 to move it into its FIG. 17,projected position.

What is claimed is:

1. A secret latch comprising a lock frame adapted to be mounted on adoor, a bolt mounted on said frame for movement between a lockingposition and an unlocking position, a knob, means for mounting said knobfor rotation on said lock frame, means for moving said bolt out of saidlocking position upon rotation of said knob, a key mechanism, means formounting said key mechanism for rotation and for axial movement relativeto said lock frame, means for moving said bolt out of said lockingposition upon rotation of said key mechanism, means for coupling saidknob to said lock frame for precluding rotation of said knob relative tosaid lock frame, and means operable upon translation of said keymechanism for uncoupling said knob from said lock frame.

2. A device as in claim 1 in which said knob is an outer knob and saidkey mechanism is disposed within said outer knob.

3. A device as in claim 1 including an inner knob and in which saidcoupling means is a control disposed within said inner knob.

4. A device as in claim 1 including means for preventing axial movementof said key mechanism.

5. A device as in claim 4 including an inner knob and in which saidpreventing means is disposed within said inner knob.

6. A device as in claim 5 in which said preventing means includes anaxially movable button movable between a preventing position and areleasing position, means for urging said button toward said releasingposition, and means for holding said button in said preventing position.

7. A secret latch including the subcombination of a retractable bolt, alock cylinder body, means for supporting said lock cylinder body fortranslation along an axis out of an extreme position, a lock cylinderplug mounted for rotation about said axis in said lock cylinder body, aknob rotatable about said axis, means for connecting said lock cylinderbody to enable said knob to retract said bolt upon translation of saidlock cylinder body along said axis, and means for connecting said lockcylinder plug to retract said bolt upon rotation of said lock cylinderplug around said axis.

8. A device as in claim 7 including means for resiliently urging saidlock cylinder body toward said extreme position.

9. A secret latch including the subcombination of a lock frame, a boltretractable on said frame, a bolt operator, a lock cylinder body, meansfor mounting said lock cylinder body on said frame for reciprocation, alock cylinder plug, means for mounting said lock cylinder plug in saidlock cylinder body for rotation relative to said lock cylinder body,means for enabling said operator to retract said bolt by reciprocationof said lock cylinder body relative to said frame, and means forretracting said bolt by rotation of said lock cylinder plug relative tosaid frame.

10. A device as in claim 9 in which said means for retracting said boltby rotation of said lock cylinder plug includes an axially movable slipjoint.

1 l. A secret latch comprising a lock frame adapted to be mounted on adoor, a bolt mounted on said lock frame for movement between a lockingposition and an unlocking position, an outer knob, means for mountingsaid outer knob for rotation relative to said lock frame, means forinterconnecting said outer knob and said bolt for moving said bolt fromsaid locking position to said unlocking position upon rotation of saidouter knob, an inner knob, means for mounting said inner knob forrotation relative to said lock frame, means for interconnecting saidinner knob and said bolt for moving said bolt from said locking positionto said unlocking position upon rotation of said inner knob, a button,means for mounting said button for axial movement in said inner knobbetween an out position and an in position, means controlled by saidbutton for holding said outer knob against rotation when said button isin said in position and for releasing said outer knob when said buttonis in said out position, a lock cylinder body, means for mounting saidlock cylinder body for axial movement in said outer knob, meansinterconnecting said lock cylinder body and said means controlled bysaid button for moving said button into said out position, a lockcylinder plug, means for mounting said lock cylinder plug for rotationin said lock cylinder body, and means controlled by said rotation ofsaid lock cylinder plug for moving said bolt from said locking positioninto said unlocking position.

12. A device as in claim 11 including a lost-motion connection betweensaid lock cylinder body and said means controlled by said button.

13. A device as in claim 11 including means for holding said button insaid in position.

14. A device as in claim 11 in which said means controlled by saidrotation of said lock cylinder plug for moving said bolt is independentof said means for interconnecting said outer knob and said bolt.

15. A secret latch comprising a lock frame, a bolt movably mounted onsaid frame, a spindle movably mounted on said frame, means forconnecting said spindle to move said bolt, a handle, means forconnecting said handle to move said spindle, means for holding saidspindle against movement on said frame, and means accessible to thethumb of a user grasping said handle for disabling said holding means,said accessible means including at least in part a rotatable keyactuatedmeans for moving said bolt.

16. A secret latch comprising a lock frame, a bolt mounted on said framefor projection and retraction, a spindle rotatably mounted on saidframe, means for connecting said spindle when rotated to retract saidbolt, a handle having an opening, means for mounting said handle on saidspindle for rotation therewith and with said opening in alignment withsaid spindle, means for holding said spindle against rotation on'saidframe, a plunger mounted on said spindle and accessible through saidopening, means for connecting said plunger to disable said holdingmeans, and means included at least in part in said plunger and operableby a key for moving said bolt.

17. A secret latch comprising a lock frame, a bolt mounted on said framefor projection and retraction, a spindle rotatably mounted on said frameand projecting therefrom along an axis, means for connecting saidspindle when rotated about said axis to retract said bolt, means forholding said spindle against rotation on said frame, a pin tumblermechanism including a body and a plug key-rotatable in said body, meansfor mounting said pin tumbler mechanism on said spindle for movementalong said axis, means operated by axial movement of said pin tumblermechanism for disabling said holding means, and means operated byrotation of said plug in said body for retracting said bolt.

18. A secret latch for a lock having a latch bolt retractable byrotation of a knob and retractable by keyrotation of a key plug in abody disposed within said knob and having means for holding said knobagainst rotation comprising means operated by depression of said keyplug and said body relative to said knob for disabling said holdingmeans.

1. A secret latch comprising a lock frame adapted to be mounted on adoor, a bolt mounted on said frame for movement between a lockingposition and an unlocking position, a knob, means for mounting said knobfor rotation on said lock frame, means for moving said bolt out of saidlocking position upon rotation of said knob, a key mechanism, means formounting said key mechanism for rotation and for axial movement relativeto said lock frame, means for moving said bolt out of said lockingposition upon rotation of said key mechanism, means for coupling saidknob to said lock frame for precluding rotation of said knob relative tosaid lock frame, and means operable upon translation of said keymechanism for uncoupling said knob from said lock frame.
 2. A device asin claim 1 in which said knob is an outer knob and said key mechanism isdisposed within said outer knob.
 3. A device as in claim 1 including aninner knob and in which said coupling means is a control disposed withinsaid inner knob.
 4. A device as in claim 1 including means forpreventing axial movement of said key mechanism.
 5. A device as in claim4 including an inner knob and in which said preventing means is disposedwithin said inner knob.
 6. A device as in claim 5 in which saidpreventing means includes an axially movable button movable between apreventing position and a releasing position, means for urging saidbutton toward said releasing position, and means for holding said buttonin said preventing position.
 7. A secret latch including thesubcombination of a retractable bolt, a lock cylinder body, means forsupporting said lock cylinder body for translation along an axis out ofan extreme position, a lock cylinder plug mounted for rotation aboutsaid axis in said lock cylinder body, a knob rotatable about said axis,means for connecting said lock cylinder body to enable said knob toretract said bolt upon translation of said lock cylinder body along saidaxis, and means for connecting said lock cylinder plug to retract saidbolt upon rotation of said lock cylinder plug around said axis.
 8. Adevice as in claim 7 including means for resiliently urging said lockcylinder body toward said extreme position.
 9. A secret latch includingthe subcombination of a lock frame, a bolt retractable on said frame, abolt operator, a lock cylinder body, means for mounting said lockcylinder body on said frame for reciprocation, a lock cylinder plug,means for mounting said lock cylinder plug in said lock cylinder bodyfor rotation relative to said lock cylinder body, means for enablingsaid operator to retract said bolt by reciprocation of said lockcylinder body relative to said frame, and means for retracting said boltby rotation of said lock cylinder plug relative to said frame.
 10. Adevice as in claim 9 in which Said means for retracting said bolt byrotation of said lock cylinder plug includes an axially movable slipjoint.
 11. A secret latch comprising a lock frame adapted to be mountedon a door, a bolt mounted on said lock frame for movement between alocking position and an unlocking position, an outer knob, means formounting said outer knob for rotation relative to said lock frame, meansfor interconnecting said outer knob and said bolt for moving said boltfrom said locking position to said unlocking position upon rotation ofsaid outer knob, an inner knob, means for mounting said inner knob forrotation relative to said lock frame, means for interconnecting saidinner knob and said bolt for moving said bolt from said locking positionto said unlocking position upon rotation of said inner knob, a button,means for mounting said button for axial movement in said inner knobbetween an out position and an in position, means controlled by saidbutton for holding said outer knob against rotation when said button isin said in position and for releasing said outer knob when said buttonis in said out position, a lock cylinder body, means for mounting saidlock cylinder body for axial movement in said outer knob, meansinterconnecting said lock cylinder body and said means controlled bysaid button for moving said button into said out position, a lockcylinder plug, means for mounting said lock cylinder plug for rotationin said lock cylinder body, and means controlled by said rotation ofsaid lock cylinder plug for moving said bolt from said locking positioninto said unlocking position.
 12. A device as in claim 11 including alost-motion connection between said lock cylinder body and said meanscontrolled by said button.
 13. A device as in claim 11 including meansfor holding said button in said in position.
 14. A device as in claim 11in which said means controlled by said rotation of said lock cylinderplug for moving said bolt is independent of said means forinterconnecting said outer knob and said bolt.
 15. A secret latchcomprising a lock frame, a bolt movably mounted on said frame, a spindlemovably mounted on said frame, means for connecting said spindle to movesaid bolt, a handle, means for connecting said handle to move saidspindle, means for holding said spindle against movement on said frame,and means accessible to the thumb of a user grasping said handle fordisabling said holding means, said accessible means including at leastin part a rotatable key-actuated means for moving said bolt.
 16. Asecret latch comprising a lock frame, a bolt mounted on said frame forprojection and retraction, a spindle rotatably mounted on said frame,means for connecting said spindle when rotated to retract said bolt, ahandle having an opening, means for mounting said handle on said spindlefor rotation therewith and with said opening in alignment with saidspindle, means for holding said spindle against rotation on said frame,a plunger mounted on said spindle and accessible through said opening,means for connecting said plunger to disable said holding means, andmeans included at least in part in said plunger and operable by a keyfor moving said bolt.
 17. A secret latch comprising a lock frame, a boltmounted on said frame for projection and retraction, a spindle rotatablymounted on said frame and projecting therefrom along an axis, means forconnecting said spindle when rotated about said axis to retract saidbolt, means for holding said spindle against rotation on said frame, apin tumbler mechanism including a body and a plug key-rotatable in saidbody, means for mounting said pin tumbler mechanism on said spindle formovement along said axis, means operated by axial movement of said pintumbler mechanism for disabling said holding means, and means operatedby rotation of said plug in said body for retracting said bolt.
 18. Asecret latch for a lock having a latch bolt retractable by rotation of aknob and retractable by key-rotation of a key plug in a body disposedwithin said knob and having means for holding said knob against rotationcomprising means operated by depression of said key plug and said bodyrelative to said knob for disabling said holding means.